1. Field of the Invention
The present invention generally relates to a remote control system for a vehicle, and especially relates to such systems in which locking/unlocking devices provided at car doors or a car trunk can be remotely locked or unlocked.
2. Description of the Related Art
A remote keyless entry system (RKE) is known in the automobile technical fields, in which car doors can be remotely locked and unlocked by manipulating a remote device including a radio transmitter. Some of such remote devices have a trunk opening function that can open a car trunk remotely. A car trunk, however, cannot be remotely closed and locked after being opened. Therefore, it is desired to avoid mismanipulation of the remote device. One scheme for preventing the mismanipulation of the remote device requires a switch of the remote device to be pressed for a certain long time to open the car trunk. In this scheme, at default setting, the remote device operates only when its switch is pressed for one second or more, that is, in a “long pressing” manner.
The long pressing manner is, however, inconvenient to some users. Therefore, dealers are allowed to modify the long pressing manner to be a short pressing manner by using a special tool at a user's request. But users have to go to the dealer to ask them to change the pressing manners.
If such a long pressing manner requires users to press the switch for too long a time, it may make the users uncomfortable. One prior technology to avoid such uncomfortableness is described in Japanese Patent Laid-Open No. 2002-229609, in which a remote device transmits an order signal to an in-vehicle device only when two conditions are met, that is, only when a signal is detected by a signal detection sensor and a manipulation switch is manipulated on the remote device.
However, these known technologies have the following problems.
In the prior remote keyless systems for opening a car trunk, for example, user's convenience and mismanipulation prevention are contrary to each other. If it is required to press a switch for a long time in order to prevent mismanipulation, that long pressing may be inconvenient for users. Car manufactures cannot grasp, due to the variety of users' tastes, how long the switch should be pressed to provide comfort for users.
Another scheme is to prepare a switch for changing between the “long pressing mode” and the “short pressing mode” depending on user's taste. This scheme needs additional space for arranging the switch, resulting in an increase in cost.